BackgroundEating Disorders pose a serious health risk to individuals. Often, eating disorder symptoms are overlooked when assessing obesity risk. The current cross-sectional study was focused on the search of association between disordered eating behaviors evaluated by Eating Attitudes Test 26 (EAT-26) and obesity in a large cohort of Russian-speaking adults seeking online assistance with medical weight correction.MethodsThe web-based cross-sectional study evaluated the data of online Eating Attitudes Test 26 (EAT-26) completed by 13,341 registered adult visitors of weight loss clinic website. The EAT-26 provides an overall score for potential eating disorders risk, as well as scores for three subscales: Bulimia, dieting, and oral control. Additional self-reported information about sex, weight, height, and age of respondents was used for analysis. The nonparametric analysis of variance and binominal logistic regression modeling were applied to search for an association between obesity and EAT-26 total score and subscales scores. The critical level of the significance was considered as α = 0.05.ResultsWomen (94%) had lower BMI values but higher EAT-26 total score than men, which was indicated as statistically significant by a Wilcoxon Signed-Ranks Test (Z = − 11.80, p < 0.0001). Logistic regression for the whole cohort revealed that Bulimia subscale score was associated with higher risk of obesity (OR = 1.03, 95% CI 1.02–1.05) whereas higher score of EAT-26 oral control subscale was associated with decreased risk of obesity (OR = 0.93, 95% CI 0.91–0.95). Separate analysis for men and women showed that in men higher obesity risk was associated with higher oral control subscale scores (OR = 1.08, 95% CI 1.06–1.11); while in women both dieting and bulimia subscales scores were associated with higher obesity risk (OR = 1.02, 95% CI 1.01–1.03 and OR = 1.03, 95% CI 1.02–1.05, respectively). Older age was associated with obesity risk for both women and men.ConclusionsIn a large cohort of individuals seeking medical weight correction assistance, the risk of obesity was associated with the higher EAT-26 scores, age, and sex. Moreover, different eating disorder risk profiles were associated with obesity in men and women. Higher oral control subscale score was associated with decreased risk of obesity in women, but with higher risk in men. Older age was a shared obesity risk factor for both sexes. Therefore, the use of EAT-26 would facilitate individual diagnostic assessment for specific eating disorders in different sub-cohorts. Further assessment of separate EAT-26 subscales may be important to predict sex-/age-specific risks of obesity that implies their study in the future.Plain English summaryObesity is a significanthealth problem. Different factors (e.g. social, biological, and behavioral) areimportant for their successful treatment. Abnormal eating behaviors may be oneof the most likely predictors of increased body weight. This study aims todetermine whether there is a significant association between obesity and scoreson the eating behavior questionnaire-Eating Attitudes Test-26 (EAT-26)-in alarge cohort of adults seeking medical weight correction assistance at a privateweight loss clinic web-site. According to the study results, the associationwas shown for the male sex, older age, and higher Bulimia scores as measured onthe EAT-26. Moreover, different EAT-26 scales were associated with obesityrisks in women and men subgroups, while older age was a shared risk factor forobesity in both sexes. The findings may suggest sex-/age-specific diagnosticapproach and treatment strategies for individuals with obesity.